Tuner drive apparatus

ABSTRACT

In a tuner cord drive, a tuner drive pulley of relatively small diameter includes a radially extending arm, the outer portion of which protrudes from the rim of the pulley and anchors one end of an extended coil spring. The drive cord is wrapped about the pulley and includes a portion that extends radially inwardly through a peripheral slot in the pulley. The other, or free, end of the extended spring is affixed to the mentioned cord portion, thereby introducing tension in the drive cord.

United States Patent Cote 1 3,668,924 1 June 13, 1972 [s41 TUNER DRIVE APPARATUS [72] Inventor: Alfred A. Cote, Langhorne, Pa. [73] Assignee: Philco-Ford Corporation, Philadelphia, Pa. [22] Filed: July 6, 1970 [21] Appl. No.: 52,581

[52] U.S. CL, ..74/10.7, 74/501 .5 [51] lnt.Cl ..Fl6h 35/18 [58] Field oiSearch ..74/l0.7, 501.5

[5 6] I References Cited UNITED STATES PATENTS 2,844,039 7/1958 Spakman ..74/l0.7

2,491,341 12/1949 Tillman ..74/10.7 2,503,220 4/1950 Schaper ..74/l0.7

Primary ExaminerMilton Kaufman Attorney-Carl H. Synnestvedt ABSTRACT In a tuner cord drive, a tuner drive pulley of relatively small diameter includes a radially extending arm, the outer portion of which protrudes from the rim of the pulley and anchors one end of an extended coil spring. The drive cord is wrapped about the pulley and includes a portion that extends radially inwardly through a peripheral slot in the pulley. The other, or free, end of the extended spring is affixed to the mentioned cord portion, thereby introducing tension in the drive cord.

4 Claim, 4 Drawing figures PATENTEDJUH13 m2 3.668.924

Z7 27 INVTOR.

44mm A. var! TUNER DRIVE APPARATUS BACKGROUND OF THE INVENTION This invention relates to tuners for radios and the like, and especially to a cord drive apparatus for such a tuner and for an indicator therefor. The apparatus is featured by an improved cord tensioning arrangement associated with a pulley over which the cord is strung.

It is a general practice in broadcast receivers, such as radios, to provide a tuning system, and an indicator therefor including a marker movable preferably in a straight line in correspondence with the rotational movement of a tuner shaft. A cord drive conveniently accommodates straight line movement of the marker. In such a drive, the cord is attached to the marker, and has one group of several turns wrapped around a manually operable shaft and another group of several turns wrapped about a drum, or pulley, that is rotatable with the tuner shaft. The cord is attached to the pulley by means of a helical spring which provides tension in the cord. While this arrangement works very well with a relatively large pulley, difficulties have been encountered whenrelatively small pulleys are used, as may be required to afford a desired difference in rotational rates between the tuner shaft and the manually operable shaft. A relatively small pulley cannot accommodate sufficient deflection of the spring to establish and maintain substantially uniform tension in the drive cord throughout the changes nor mally encountered in length of the cord.

It is a general objective of this invention to provide, on a pulley of relatively small diameter, an improved helical spring mounting and retaining means that overcomes the aforementioned difficulties.

SUMMARY OF THE INVENTION In achievement of the foregoing as well as other objectives, the present invention contemplates the provision, in a tuner drive, of a drive pulley of relatively small diameter including a radially extending projection, or arm portion, protruding from the rim of the pulley, a drive cord wrapped about said pulley and including a portion extending radially inwardly through a peripheral opening in the pulley, and an extended coil spring affixed at one end to an outer end region of said arm portion, and afiixed at its free end to said radially inwardly extending portion of said cord thereby to tension the latter.

The manner in which the foregoing as well as other objectives andadvantages of the invention may best be achieved will be more fully understood from a consideration of the ensuing description, taken in light of the accompanying drawing.

. BRIEF DESCRIPTION OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENT -With reference to FIG. 1, a radio receiver 10, of known type, includes a rotary tuner 11 provided with a shaft extension 12 and a pulley l3 thereon. The invention is particularly concerned with the construction of pulley 13, which will be explained in detail below. However it should be understood that pulley l3, and hence tuner 11, is driven by a manually operable knob 14 through cord 15 including a portion wrapped about the pulley and a portion wrapped about a shaft 16 that carries knob 14 and is joumalled for rotation in suitable bearing means, one of which is seen at 17. In the particular embodiment illustrated, a pair of rounded posts 19 and 20 have portions of cord 15 strung thereover and are located to establish and maintain substantial alignment of the respective wraps of the cord about pulley l3 and shaft 16. The cord 15 further is wrapped about a pair of rounded posts 21 and 22. The portion of cord 15 extending between posts 21 and 22 is threaded through a linearly movable pointer 23 frictionally retained on the cord and slidable, in known manner, on an edgeportion of the radio cabinet having thereon a conventional station radio frequency scale 8.

In especial accordance with the invention, and with reference also to FIGS. 2 and 3, pulley 13 is of relatively small diameter, in provision of a desired rotational ratio between knob 14 and tuner shaft 12, and includes a radially extending arm 24 protruding from the rim of the pulley. The section of the drive cord wrapped about pulley 13 includes a portion extending radially inwardly through a peripheral opening 25 in the pulley disposed substantially diametrically opposite arm 24. An extended coil spring 26 is affixed at one end to an outer end region of arm 24, and is affixed at its free end to the radially inwardly extending portion 15a of the cord. Conveniently, and as is shown in the drawing, the inwardly extending cord portion 15a comprises individually looped ends of the cord through which the hook 29 of the spring extends.

As seen to advantage in FIG. 3, the rim of pulley 13 is generally channel shaped, and arm 24 comprises an extension of one of the leg portions thereof. The rim portion of the pulley includes an aperture 27in the region of the base of arm 24, and the arm includes a tranversely extending aperture 28 in the region of its outer end portion.

Spring 26 is coiled helically, and has a hook 29 at one end that attaches it to cord 15. The other end of the spring includes a reversely bent hook portion 30, the loop section of which extends through aperture 28 in arm 24. Beyond the 'loop section is a leg portion 30a that extends along arm 24 and protrudes radially inwardly through the aperture27 in the rim of the pulley. The end of leg portion 30a is bent, as seen at 30b, to extend transversely of the leg portion and project adjacent the cylindrically shaped section'of the rim portion of the pulley, in the vicinity of aperture 27. By such construction, and as will be more fully appreciated from FIG. 4, were cord 15 to break, and spring 26 assume its illustrated relaxed position as seen at 26a, it would be restrained from falling from the pulley. Thus, the danger of the spring falling into the electrical circuitry is eliminated.

Moreover it will be appreciated that although the pulley is of relatively small diameter, for reasons stated, the extension thereon accommodates useful deflection of a coil spring that is longer than normally could be mounted on a pulley of such diameter. By this construction, a substantial reserve of tensioning force is available over a wide range of changes in length of the cord, such as may arise through changes in temperature and humidity.

I claim:

1. In tuner apparatus of the type including a cord drive having a manually rotatable shaft, a linearly movable frequency indicator, a rotary tuner, a pulley rotatable with said tuner, anda drive cord strung over said shaft and said pulley, and including a portion affixed to said indicator to move the same, the improvement comprising: means providing a projection on said pulley protruding generally radially beyond the rim portion thereof; means defining a first aperture in the rim portion of said pulley and circumferentially spaced from said projection; means defining a second aperture in the rim portion of said pulley, in the region of said projection; said cord including a loop portion extending through said first aperture and substantially radially inwardly of said pulley; said projection including a transversely extending aperture in the region of the recited outer portion thereof; and helical cord-tensioning spring means having one end afiixed to said cord, and the other end including a reversely bent hook portion the loop of which portion extends through the aperture in said projection and the end of which portion extends along said projection and protrudes through said second aperture.

2. Apparatus according to claim 1, and further characterized in that the recited end of said hook portion is bent to extend transversely and project adjacent said rim portion in the region of said second aperture, thereby to provide retention of said spring in the event of breakage of said cord.

3. In a cord drive: a pulley; a radially extending arm on said pulley protruding from the rim thereof, said arm including a transversely extending aperture in the region of the outer end portion thereof; means defining a first aperture in the rim of said pulley and circumferentially spaced from said arm; means defining a second aperture in the rim of said pulley in the region of said arm; a cord strung over said pulley, including a loop portion extending through said first aperture, substantially radially inwardly of said pulley; and helical spring means including a portion extending along said arm and between an outer region of said arm and said loop portion of said cord, thereby to tension said cord, one end of said spring means being afiixed to said cord, and the other end including a reversely bent hook portion the loop of which portion extends through the aperture in said arm and the end of which portion extends along said arm and protrudes through said second aperture.

4. The drive according to claim 3, and further characterized in that the recited end of said hook portion is bent to extend transversely and project adjacent said rim portion in the region of said second aperture, thereby to provide retention of said spring in the event of breakage of said cord. 

1. In tuner apparatus of the type includinG a cord drive having a manually rotatable shaft, a linearly movable frequency indicator, a rotary tuner, a pulley rotatable with said tuner, and a drive cord strung over said shaft and said pulley, and including a portion affixed to said indicator to move the same, the improvement comprising: means providing a projection on said pulley protruding generally radially beyond the rim portion thereof; means defining a first aperture in the rim portion of said pulley and circumferentially spaced from said projection; means defining a second aperture in the rim portion of said pulley, in the region of said projection; said cord including a loop portion extending through said first aperture and substantially radially inwardly of said pulley; said projection including a transversely extending aperture in the region of the recited outer portion thereof; and helical cord-tensioning spring means having one end affixed to said cord, and the other end including a reversely bent hook portion the loop of which portion extends through the aperture in said projection and the end of which portion extends along said projection and protrudes through said second aperture.
 2. Apparatus according to claim 1, and further characterized in that the recited end of said hook portion is bent to extend transversely and project adjacent said rim portion in the region of said second aperture, thereby to provide retention of said spring in the event of breakage of said cord.
 3. In a cord drive: a pulley; a radially extending arm on said pulley protruding from the rim thereof, said arm including a transversely extending aperture in the region of the outer end portion thereof; means defining a first aperture in the rim of said pulley and circumferentially spaced from said arm; means defining a second aperture in the rim of said pulley in the region of said arm; a cord strung over said pulley, including a loop portion extending through said first aperture, substantially radially inwardly of said pulley; and helical spring means including a portion extending along said arm and between an outer region of said arm and said loop portion of said cord, thereby to tension said cord, one end of said spring means being affixed to said cord, and the other end including a reversely bent hook portion the loop of which portion extends through the aperture in said arm and the end of which portion extends along said arm and protrudes through said second aperture.
 4. The drive according to claim 3, and further characterized in that the recited end of said hook portion is bent to extend transversely and project adjacent said rim portion in the region of said second aperture, thereby to provide retention of said spring in the event of breakage of said cord. 